There are five other colour variants for this set in the artwork database, and all are in the game and mostly complete. However three of those are only available as poor or common quality and so not currently transmoggable. See:

Dark brown (officially "Black"): Transmoggable helm, shoulders, chest and belt, see this link (also included gloves but they are no longer obtainable). Not transmoggable: Rough Leather Set (common quality)

(Note that the common and poor sets listed above have no transmog pages. You'll have to click on the links to view the appearances and lists of pieces).